azelaic acidretinol
Limited pairing evidencelimited evidence
Evidence for this pairing is limited.
An open-label comparative trial (48 patients with melasma) found combining azelaic acid 20% with tretinoin 0.1% produced faster and slightly more complete improvement than azelaic acid alone — 79% of the combination group reached "excellent or good" improvement at 6 months vs. 71% with azelaic acid alone, and visible lightening started by week 6 rather than week 9. It's a single small, unblinded trial reaching us through an independent review's synthesis rather than a source we could verify directly, and it tested prescription-strength tretinoin rather than OTC retinol, so treat the specific numbers as suggestive, not settled.